Solar Energy Fundamentals

Question 1

What is proportional to the energy used?

Answer 1

The length of time a load is on

Question 2

When does the sun set in the same place on the horizon?

Answer 2

At winter solstice

Question 3

The azimuth of solar (true) south is -24 of a magnetic compass in San Francisco, CA. Your array is aiming to the heading of what degree?

Answer 3

189 degrees

Question 4

When the sun sets on summer solstice, which direction is the farthest that it will ever set?

Answer 4

North

Question 5

At what point is it the same day everywhere in the world at the same time?

Answer 5

Equinox

Question 6

In St. Paul MN, is the sun up the same amount of hours as there are sun hours per day?

Answer 6

No

Question 7

How does the amount of sun falling on higher elevations compare to lower elevations?

Answer 7

Greater

Question 8

If a site gets an average of 5.3 sun hours per day according to the National Renewable Energy Laboratories for a particular city and the home uses 10 kilowatt hours per day on average, what size grid-tied, net metered system would most closely offset the energy usage?

Answer 8

2.45 kw PV system

Question 9

When is the sun farthest north?

Answer 9

Summer solstice

Question 10

What surfaces of the earth receive the most amount of sun?

Answer 10

Surfaces at higher elevations

Question 11

In Oakland, California, the sun will never do what?

Answer 11

Have a zenith angle of zero

Question 12

In St. Paul MN, how many hours is the sun up, compared with the number of sun hours per day?

Answer 12

More hours

Question 13

When irradiance increases what happens to the I-V curve?

Answer 13

The curve shifts up

Question 14

The altitude angle is the angle of what?

Answer 14

The angle from zenith to the horizon

Question 15

What is an example of solar irradiation?

Answer 15

5.5 sun hours per day

Question 16

What is sinusoidal, bimodal, and indirect energy in an off-grid system?

Answer 16

Solar and wind energy

Question 17

5.5 sun hours is an example of what?

Answer 17

Solar irradiation

Question 18

What is an equinox?

Answer 18

The time or date (twice each year) at which the sun crosses the celestial equator, when day and night are of equal length

Question 19

Are solar power, unit area, and solar efficiency, time factors for insolation measurement?

Answer 19

No

Question 20

Every year the sun does what on the winter solstice?

Answer 20

The sun sets in the same place on the horizon

Question 21

A water pump only pumps when the sun is out, by tilting the array more than the latitude angle, what amount of water do you pump?

Answer 21

Pump the same amount of water every month during the year

Question 22

You can use what to account for colder temperatures causing higher voltage?

Answer 22

A temperature correction factor, weather trends that include record low temperatures, and/or a typical string sizing program from an inverter manufacturer found on the internet

Question 23

What is more prevalent in isolated communities?

Answer 23

Battery based systems

Question 24

In locations with what kind of latitude does the sun rise further to the north in the winter?

Answer 24

Higher latitudes

Question 25

What happens on a higher latitude?

Answer 25

The sun will rise further to the north in the winter than in lower latitudes

Question 26

If a site gets an average of 5.3 sun hours per day, about how many kilowatt hours would a 1 kw system produce?

Answer 26

1500 kwh

Question 27

In Oakland, California, how many times will the sun have a zenith angle of zero?

Answer 27

Never

Question 28

What is a condition of STC

Answer 28

100 watts per square meter of sunlight intensity, 25 degrees Celsius, and/or airmass of 1.5

Question 29

Solar energy and unit area are considered what type of measurement?

Answer 29

Insolation measurement

Question 30

A water pump only pumps when the sun is out. If you need to pump the same amount of water every month of the year, what would you do?

Answer 30

Tilt the array more than the latitude angle

Question 31

In an I-V curve, when does the curve shift up?

Answer 31

As irradiance increases

Question 32

What will happen to an I-V curve when there is more sunlight?

Answer 32

The curve rises vertically

Question 33

What factors do an insolation measurement take into account?

Answer 33

Solar energy and Unit area

Question 34

Where are battery based systems more prevalent?

Answer 34

In isolated communities

Question 35

What do you call the combination of solar and wind energy in an off-grid system?

Answer 35

Hybrid

Question 36

What factors are considered in an insolation measurement?

Answer 36

Solar energy and unit area